1. Field of the Invention
The present invention relates, generally, to a light modulator module package, and more particularly, to a light modulator module package, which has a minimal size and efficiently disperses heat, while maintaining the optical properties of a light modulator device.
2. Description of the Related Art
Recently, micro-machining techniques for fabricating micro-optical components, such as micro-mirrors, micro-lenses or switches, micro-optical sensors, micro-biochips, and-micro-wireless communication devices, using a process of manufacturing a semiconductor device, have been developed. MEMS (Micro-Electro-Mechanical Systems), concerning the micro-machining techniques, and the devices and systems fabricated by such techniques, are regarded as rapidly growing technologies in a broad range of commercial applications.
In particular, the micro-mirror has been commercially applied to large image displays, optical signal distributors, bar-code scanners, or optical signal decay units, or research for commercialization thereof is under study.
FIG. 1 is a perspective view showing a conventional grating light modulator using electrostatic force, which is disclosed in U.S. Pat. No. 5,311,360.
As shown in FIG. 1, a light modulator 10 disclosed in U.S. Pat. No. 5,311,360 has a plurality of equally spaced-apart deformable grating elements 18, each of which includes a light-reflective planar surface and is suspended above a silicon substrate 16. Further, an insulating layer 11 is deposited on the substrate 16, after which a sacrificial silicon dioxide layer 12 is deposited.
The silicon dioxide layer 12 is partially etched in such a way that the grating elements 18 are supported on the silicon dioxide layer 12 by a nitride frame 20.
To modulate light having a single wavelength of λ0, the modulator 10 is designed so that the thicknesses of the grating elements 18 and the silicon dioxide layer 12 total one quarter of λ0.
The grating amplitude of the modulator 10, which is defined by a vertical distance d between the reflective surfaces of the grating elements 18 and the reflective surface of the substrate 16, is controlled by applying the voltage between the grating elements 18 and the substrate 16.
However, since the light modulator disclosed in U.S. Pat. No. 5,311,360 uses electrostatic force for position control of the micro-mirror, the switching voltage is relatively high (about 3 V) and the relationship between the applied voltage and the displacement is not linear, therefore resulting in unreliable light control.
To overcome the above problems, thin-film piezoelectric light modulators have been proposed.
In this regard, a conventional diffractive thin-film piezoelectric light modulator is shown in FIG. 2.
As shown in FIG. 2, the conventional diffractive thin-film piezoelectric light modulator 100 includes a silicon substrate 101 having a depressed portion, an etching prevention layer 102 formed on the silicon substrate 101, a lower support 111 having both ends of a bottom surface thereof attached to the silicon substrate 101 on both sides of the depressed portion of the substrate 101 to cover the depressed portion of the substrate 101, lower electrode layers 112 and 112′ formed on both sides of the lower support 111, piezoelectric material layers 113 and 113′ formed on the lower electrode layers 112 and 112′, upper electrode layers 114 and 114′ formed on the piezoelectric material layers 113 and 113′, and a micro mirror 115 formed at a central position on the lower support 111.
As such, it is preferable that such a conventional diffractive thin-film piezoelectric light modulator 100 be modularized to be commercially available. For modularization, various characteristics should be considered.
Generally, in the conventional diffractive thin-film piezoelectric light modulator 100, a drive integrated circuit is manufactured on another substrate and then modularized in hybrid form, rather than being integrated on the same die, resulting in high yields and low fabrication costs. Thus, the light modulator has been preferably manufactured in hybrid form.
However, since the conventional diffractive thin-film piezoelectric light modulator 100 uses light, it cannot utilize the common modularization structure and process unchanged, unlike general devices, and also, it requires specialized components.
In addition, the conventional diffractive thin-film piezoelectric light modulator 100 is disadvantageous because its active device has very low resistance to moisture due to structural properties, and hence, needs to be sealed from the exterior. Further, to stabilize operating properties and increase the lifetime of the device, the diffractive thin-film piezoelectric light modulator 100 should be designed to efficiently disperse heat generated when operating the device and irradiating light.